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24 tháng 1 2017

Gọi số trận đấu mà anh Nam chơi ngày thứ nhất, thứ 2, ..., ngày thứ 20 lần lược là: a1; a2; ...; a n.

Xét 20 tổng :

S1 = a1

S2 = a1 + a2

...................

S n = a1 + a2 + ... + a​ n

Ta có: S1 < S2 < .... < S n < 36 (vì trong 20 ngày anh Nam không chơi quá 12.3 = 36 trận)

Ta biết rằng 1 số tự nhiên bất kỳ khi chia cho 20 thì có 19 số dư khác 0 là: 1, 2,...,19.

Giờ quay lại bài toán ta thấy 

Nếu trong 20 tổng này có 1 tổng chia hết 20 thì bài toán đã được chứng minh (vì các tổng đó lớn hơn 0 nhỏ hơn 36 nên tổng chỉ có thể là 20). 

Còn nếu trong 20 tổng này không có tổng nào chia hết cho 20 thì sẽ tồn tại ít nhất 2 tổng có cùng số dư khi chia cho 20.

Giả sử hai tổng đó là S m, S n (m > n) thì ta có S m - S n = (a1 + a2 + ... + a m) - (a1 + a2 + ... + a n) = a n+1 + a n+2 + ...+ a​ m chia hết cho 20. Hay S m - S​ n = 20.

Vậy tồn tại một số ngày liên tiếp trong đó anh chơi đúng 20 trận.

25 tháng 1 2017

20 đấy Vương ạ

18 tháng 6 2021

\(\sqrt{30}\)

18 tháng 6 2021

Bằng 5,490838311

II. Choose the best answer (A, B, C or D).7.I was                          to learn that the director of that gripping film has won the first prize. A.interestB.interestsC.interestedD.interesting8.The film was so                           . However my father saw it from beginning to end. A.fascinatedB.excitedC.boringD.fascinating9.We were                            with the latest film of that director.  A.satisfiedB.satisfactoryC.satisfyingD.satisfy10.We like the film very much. The...
Đọc tiếp

II. Choose the best answer (A, B, C or D).

7.

I was                          to learn that the director of that gripping film has won the first prize.

 

A.

interest

B.

interests

C.

interested

D.

interesting

8.

The film was so                           . However my father saw it from beginning to end.

 

A.

fascinated

B.

excited

C.

boring

D.

fascinating

9.

We were                            with the latest film of that director.

 

 

A.

satisfied

B.

satisfactory

C.

satisfying

D.

satisfy

10.

We like the film very much. The                                are incredible and the plot is gripping.

 

A.

characters

B.

acting

C.

styles

D.

story

11.

I have never felt as                             as I did when I watched that horror film.

 

A.

terrify

B.

terrified

C.

terrifying

D.

terrible

12.

Not many people went to see the film;                                  , it received good reviews from critics.

 

A.

although

B.

but

C.

despite

D.

nevertheless

13.

Let’s go to the Victor Cinema. I’m sure you’ll find the film                                    .

 

A.

excites

B.

excite

C.

excited

D.

exciting

14.

Last night, I didn’t go to bed early                                   being very tired.

 

A.

because of

B.

although

C.

despite of

D.

in spite of

15. I went to the cinema with my friends yesterday                         feeling very tired.

 

A.

A. although

B.

B. so

C.

C. in spite of

D.

D. but

 

16. We didn’t find it funny                        it was a comedy.

 

 

 

A.

A. but

B.

B. although

C.

C. despite

D.

D. in spite of

 

17. I enjoy the film on TV yesterday evening                           nobody in my family liked it.

 

                 

            A. so                            B. yet                           C. but                          D. in spite of

18. In 1939, this ..................... was made to tell stories about the real life of Abraham Lincoln as a young man.

            A. biopic                                                         B. science fiction film

            C. action film                                                  D. horror film

      19. My son feels very happy when he sees that ..................... with a lot of cute animals.

            A. horror film             B. biopic                     C. thriller film             D. animation

      20. Most ..................... say that this film is worth watching.

            A. plots                       B. settings                   C. critics                      D. acting

      21. He acts very well. I’m sure that yesterday he stayed up all night reading the ...............

            A. acting                      B. character               C. survey                    D. script

      22. Before you go to the cinema, you can watch the trailer and read .............. of the film.

            A. reviews                  B. disaster                  C. critic                        D. character

      23. That was a ................ and boring horror film so I slept from the beginning to the end.

            A. shocking                 B. entertaining           C. gripping                  D. predictable

      24. I didn’t expect the movie to be so interesting and so .....................! I cried at the end of the film.

            A. moving                   B. violent                    C. confusing               D. hilarious

      25. According to our latest survey, Batman is one of 10 ..................... films this summer.

            A. must-see                B. violence                  C. embarrassed         D. stunt

      26. Woody Allen is one of some directors who ..................... in their own films and receive positive reviews.

            A. set                           B. star                         C. recommend           D. make

      27. The film had such a sudden and ..................... ending that no one can imagine.

            A. disappointed         B. must-see                C. predictable             D. shocking

      28. Watching ..................... films may make people more aggressive.

            A. hilarious                 b. violent                     C. entertaining           D. gripping

6
18 tháng 6 2021

1d,2c,3a,4a,5b,6d,7d,8d,9d,10d,11c,12a,13c,14d,15b,16c,17c,18a,19d,20b.Xin lỗi cậu tớ chỉ làm được đến đấy thôi!
 

18 tháng 6 2021
Bài có thế mà cũng không làm được đúng là ngu đần
II. Choose the best answer (A, B, C or D).7.I was                          to learn that the director of that gripping film has won the first prize. A.interestB.interestsC.interestedD.interesting8.The film was so                           . However my father saw it from beginning to end. A.fascinatedB.excitedC.boringD.fascinating9.We were                            with the latest film of that director.  A.satisfiedB.satisfactoryC.satisfyingD.satisfy10.We like the film very much. The...
Đọc tiếp

II. Choose the best answer (A, B, C or D).

7.

I was                          to learn that the director of that gripping film has won the first prize.

 

A.

interest

B.

interests

C.

interested

D.

interesting

8.

The film was so                           . However my father saw it from beginning to end.

 

A.

fascinated

B.

excited

C.

boring

D.

fascinating

9.

We were                            with the latest film of that director.

 

 

A.

satisfied

B.

satisfactory

C.

satisfying

D.

satisfy

10.

We like the film very much. The                                are incredible and the plot is gripping.

 

A.

characters

B.

acting

C.

styles

D.

story

11.

I have never felt as                             as I did when I watched that horror film.

 

A.

terrify

B.

terrified

C.

terrifying

D.

terrible

12.

Not many people went to see the film;                                  , it received good reviews from critics.

 

A.

although

B.

but

C.

despite

D.

nevertheless

13.

Let’s go to the Victor Cinema. I’m sure you’ll find the film                                    .

 

A.

excites

B.

excite

C.

excited

D.

exciting

14.

Last night, I didn’t go to bed early                                   being very tired.

 

A.

because of

B.

although

C.

despite of

D.

in spite of

15. I went to the cinema with my friends yesterday                         feeling very tired.

 

A.

A. although

B.

B. so

C.

C. in spite of

D.

D. but

 

16. We didn’t find it funny                        it was a comedy.

 

 

 

A.

A. but

B.

B. although

C.

C. despite

D.

D. in spite of

 

17. I enjoy the film on TV yesterday evening                           nobody in my family liked it.

 

                 

            A. so                            B. yet                           C. but                          D. in spite of

18. In 1939, this ..................... was made to tell stories about the real life of Abraham Lincoln as a young man.

            A. biopic                                                         B. science fiction film

            C. action film                                                  D. horror film

1
18 tháng 6 2021

II. Choose the best answer (A, B, C or D).

7.

I was                          to learn that the director of that gripping film has won the first prize.

 

A.

interest

B.

interests

C.

interested

D.

interesting

8.

The film was so                           . However my father saw it from beginning to end.

 

A.

fascinated

B.

excited

C.

boring

D.

fascinating

9.

We were                            with the latest film of that director.

 

 

A.

satisfied

B.

satisfactory

C.

satisfying

D.

satisfy

10.

We the film very much. The                                are incredible and the plot is gripping.

 

A.

characters

B.

acting

C.

styles

D.

story

11.

I have never felt as                             as I did when I watched that horror film.

 

A.

terrify

B.

terrified

C.

terrifying

D.

terrible

12.

Not many people went to see the film;                                  , it received good reviews from cris.

 

A.

although

B.

but

C.

despite

D.

nevertheless

13.

Let’s go to the Victor Cinema. I’m sure you’ll find the film                                    .

 

A.

excites

B.

excite

C.

excited

D.

exciting

14.

Last night, I didn’t go to bed early                                   being very tired.

 

A.

because of

B.

although

C.

despite of

D.

in spite of

15. I went to the cinema with my friends yesterday                         feeling very tired.

A. although

B.

B. so

C.

C. in spite of

D.

D. but

16. We didn’t find it funny                        it was a comedy.

 

 

A. but

B.

B. although

C.

C. despite

D.

D. in spite of

17. I enjoy the film on TV yesterday evening                           nobody in my family d it.

                 

            A. so                            B. yet                           C. but                          D. in spite of

18. In 1939, this ..................... was made to tell stories about the real life of Abraham Lincoln as a young man.

            A. biopic                                                         B. science fiction film

            C. action film                                                  D. horror film

23 tháng 9 2019

(-2)240 và (-3)160

Đưa về cùng mũ 80 ta có

(-2)240 = (-23)80 = (-8)80

(-3)160 = (-32)80 = (-9)80

Vì -8 > -9 => (-2)240 > (-3)160

18 tháng 6 2021

a) Ta có M + (5x2 - 2xy) = 6x2 + 9xy - y2

=> M = 6x2 + 9xy - y2 - (5x2 - 2xy) = x2 + 11xy - y2

b) Ta có M - (3xy - 4y2) = x2 - 7xy + 8y2

=> M =  3xy - 4y2 + x2 - 7xy + 8y2 = 4y2 - 4xy + x2

c) Ta có (25x2y - 13xy + y3) - M = 11x2y - 2y2

=> M =  (25x2y - 13xy + y3) -  (11x2y - 2y2) = 14x2y - 13xy + y3 + 2y2

d) Ta có M + (12x4 - 15x2y + 2xy2 + 7) = 0

=> M =  -12x4 + 15x2y - 2xy2 - 7

18 tháng 6 2021

còn cái nịt tui lớp 3 sao biết

II. Choose the best answer (A, B, C or D).                                                                                                                                               19. My son feels very happy when he sees that ..................... with a lot of cute animals.            A. horror film             B. biopic                     C. thriller film             D. animation      20. Most ..................... say that this film is worth watching.            A....
Đọc tiếp

II. Choose the best answer (A, B, C or D).                                                                                                                                               

19. My son feels very happy when he sees that ..................... with a lot of cute animals.

            A. horror film             B. biopic                     C. thriller film             D. animation

      20. Most ..................... say that this film is worth watching.

            A. plots                       B. settings                   C. critics                      D. acting

      21. He acts very well. I’m sure that yesterday he stayed up all night reading the ...............

            A. acting                      B. character               C. survey                    D. script

      22. Before you go to the cinema, you can watch the trailer and read .............. of the film.

            A. reviews                  B. disaster                  C. critic                        D. character

      23. That was a ................ and boring horror film so I slept from the beginning to the end.

            A. shocking                 B. entertaining           C. gripping                  D. predictable

      24. I didn’t expect the movie to be so interesting and so .....................! I cried at the end of the film.

            A. moving                   B. violent                    C. confusing               D. hilarious

      25. According to our latest survey, Batman is one of 10 ..................... films this summer.

            A. must-see                B. violence                  C. embarrassed         D. stunt

      26. Woody Allen is one of some directors who ..................... in their own films and receive positive reviews.

            A. set                           B. star                         C. recommend           D. make

      27. The film had such a sudden and ..................... ending that no one can imagine.

            A. disappointed         B. must-see                C. predictable             D. shocking

      28. Watching ..................... films may make people more aggressive.

            A. hilarious                 b. violent                     C. entertaining           D. gripping

1
18 tháng 6 2021

II. Choose the best answer (A, B, C or D).                                                                                                                                               

19. My son feels very happy when he sees that ..................... with a lot of cute animals.

            A. horror film             B. biopic                     C. thriller film             D. animation

      20. Most ..................... say that this film is worth watching.

            A. plots                       B. settings                   C. cris                      D. acting

      21. He acts very well. I’m sure that yesterday he stayed up all night reading the ...............

            A. acting                      B. character               C. survey                    D. script

      22. Before you go to the cinema, you can watch the trailer and read .............. of the film.

            A. reviews                  B. disaster                  C. cri                        D. character

      23. That was a ................ and boring horror film so I slept from the beginning to the end.

            A. shocking                 B. entertaining           C. gripping                  D. predictable

      24. I didn’t expect the movie to be so interesting and so .....................! I cried at the end of the film.

            A. moving                   B. violent                    C. confusing               D. hilarious

      25. According to our latest survey, Batman is one of 10 ..................... films this summer.

            A. must-see                B. violence                  C. embarrassed         D. stunt

      26. Woody Allen is one of some directors who ..................... in their own films and receive positive reviews.

            A. set                           B. star                         C. recommend           D. make

      27. The film had such a sudden and ..................... ending that no one can imagine.

            A. disappointed         B. must-see                C. predictable             D. shocking

      28. Watching ..................... films may make people more aggressive.

            A. hilarious                 b. violent                     C. entertaining           D. gripping

16 tháng 6 2021
Gửi bạn nè

Bài tập Tất cả

17 tháng 6 2021

Trong bài này ta có (-2)^66
Vì mũ của nó là số chẵn nên kết quả là số dương nhé bạn

15 tháng 6 2021
Gửi bạn ná😊😀😁😊😀😁😃😄😉😯😐😑😕

Bài tập Tất cả

Bài tập Tất cả

Bài tập Tất cả

15 tháng 6 2021

Bài 3 :

+, M +N = ( 2x2 -2xy -3y2 +1 ) + ( x2 -2xy +3y2 -1 )

M +N = 2x2 -2xy -3y2 +1 + x2 -2xy +3y2 -1

= ( 2x2 + x2 ) + ( -2xy -2xy ) + ( -3y2 +3y2 ) + ( 1-1 )

= 3x2 -4xy

+, M-N = ( 2x2 - 2xy - 3y2 + 1 ) - ( x - 2xy + 3y2 -1 )

= 2x2 - 2xy - 3y2 + 1 - x2 + 2xy  - 3y2 + 1

= ( 2x2 - x2 ) + ( -2xy + 2xy ) + ( -3y2 -3y2 ) + ( 1 + 1 )

= x2 - 6y2 + 2